Computing and communication networks typically include nodes, such as routers, firewalls, switches or gateways, which transfer or switch data, such as packets, from one or more sources to one or more destinations. The nodes may operate on the packets as the packets traverse the network, such as by forwarding or filtering packet-based network traffic.
Nodes may perform network address translation (NAT) operations to allow network addresses (e.g., Internet Protocol (IP) addresses) to be allocated for communication sessions that are active and/or are being established. The nodes may allocate, to the sessions, sets of ports (e.g., port blocks), associated with the network addresses, that allow traffic flows, associated with the communication session, to be transported via the ports.
The nodes may also perform the NAT operations to allow other network addresses to be released from sessions that have expired and/or are no longer active. The nodes may release, from the sessions, other port blocks, associated with the other network addresses. Releasing the network addresses and/or the port blocks may allow the network addresses and/or port blocks to be reallocated to other communication sessions. The nodes may, thus, perform the NAT operations in a manner that avoids exhausting available network addresses.